1. Field of the Invention
The present invention relates to a method of, and a system for, displaying the distribution of the magnitudes of a scalar quantity. By way of example, the scalar quantity distributions include analytical results obtained using computers, such as the results of structural analyses and other scientific and technological computations, the analyzed results of meteorologic data and geographic data sent from artificial satellites, and the analyzed results of data obtained with measuring instruments in the fields of engineering, physics, chemistry, medical science etc.
2. Description of the Related Art
A method wherein, in regard to an object to be displayed having a certain shape, a scalar quantity distribution, which is a result analyzed with a computer, is displayed in terms of contour lines or a color map, and is common in the CAE (Computer Aided Engineering) field.
In the computer aided analysis, the structure of the object is expressed by meshes, and the magnitudes of the scalar quantity having been analytically obtained at the positions of such constituents of the meshes as planes, lines and nodes are bestowed as the attribute values of the constituents. The distributional situation of the magnitudes of the scalar quantity on the meshes is displayed by the use of the contour lines or the color map.
Meanwhile, in a case where the data items of a physical quantity, such as temperature or the intensity of an electromagnetic wave, measured by a measuring apparatus are to be displayed in colors, it is common practice that the data items of the physical quantity are classified into several levels, and that the data items existing at the individual levels are substituted by color tones held in correspondence with the respective levels beforehand. Thus, the data items are color displayed in the pixel unit of a screen.
In this case, however, dividing the distributional range of the scalar quantity for the line display or the color display becomes a problem. Heretofore, the color map display has been generally presented by first finding the maximum value and minimum value of the scalar quantity analytically obtained and then equally dividing the corresponding interval by the number of the display colors of the color map.
By way of example, in the case of the color map display of the result of a structural analysis in the CAE, the magnitudes of the scalar quantity bestowed as the attribute values on the nodes of the meshes expressing the structure of the object to-be-analyzed are held in correspondence with the respective display colors of a color bar, the parts of the object between the nodes are displayed in terms of the contour lines by utilizing the linear interpolation, and the parts between the contour lines are expressed in the corresponding display colors of the color bar.
Incidentally, in the body of this specification and the statements of the appended claims, the word "color" shall cover, not only a chromatic color such as red or blue, but also an achromatic color such as white or black.
Besides, the expression "color map" shall cover, not only a display in "color", but also a gradation display such as a display in various gradations of grey.
Referring back to the prior art method, the interval defined by the maximum value and minimum value of all the magnitudes of the scalar quantity is equally divided. Therefore, if the scalar quantity has any singular value which is widely different from the tendency of the whole distribution, the singular value has an effect on the maximum or minimum value and spreads the full interval. Accordingly, in the contour line display, the contour lines become dense at the part of the object exhibiting the singular value and become sparse at the other parts. Consequently, the part which does not exhibit the singular value cannot be displayed in detail.
Moreover, in a case where a plurality of analyzed results are to be compared in terms of color maps, the above method cannot make an absolute comparison based on display colors because the display colors corresponding to the magnitudes of the scalar quantity are relatively determined for each of the analyzed results.
Meanwhile, in "INTERFACE", August 1990, pp. 221-232, a paper entitled "Image Processing of Data from Artificial Satellite" has introduced a method wherein, in order to express the distribution of image data sent from an artificial satellite, the respective level values are counted, and a histogram is displayed with the level values taken on the axis of abscissas and the number of times taken on the axis of ordinates. This method, however, cannot simultaneously display the histogram and a map and is problematic in operability and ease of data acknowledgement.